Does anyone know if faulty sensor can cause pinking? Its on a 1150 which was pinking but when the sensor was unplugged seemed to fix it. Is this the likely cause?
Thanks
Thanks
Lamda causing pinking?
- Thread starter mike wright
- Start date
Sergeant Pluck
Registered user
I'd have thought unplugging the lambda just puts the ECU into 'limp home mode' ie. runs rich hence less pinking, and doesn't necessarily tell you that the lambda itself is foobarred. In fact I'd be more inclined to think that the sensor is probably working ok if you get a positive difference with it disconnected 
Is the bike modded? Y-piece etc?
Is the bike modded? Y-piece etc?
I'd have thought unplugging the lambda just puts the ECU into 'limp home mode' ie. runs rich hence less pinking, and doesn't necessarily tell you that the lambda itself is foobarred. In fact I'd be more inclined to think that the sensor is probably working ok if you get a positive difference with it disconnected
Is the bike modded? Y-piece etc?
Yes it has a Y piece and Pipercross Air filter. The no silencer just a cat/silencer and stubbie on the end of that.
Pity you don't live near Rainbow Mike.....
A friendly dealer would, within two minutes, tell you if the Lamda sensor was awol or not just by 'plugging in' to the diagnostic machine thingy
Micky
A friendly dealer would, within two minutes, tell you if the Lamda sensor was awol or not just by 'plugging in' to the diagnostic machine thingy
Micky
Sergeant Pluck
Registered user
Thats where I'd be looking then. Sounds like the system is running too lean. Remember the ECU on the 1150 is very basic and can't cope with a any old set-up. Do a search for Steptoes CCP jumper - or try running it without the Cat Code Plug installed, that worked well on my GS's (remember to reset the motronic when you make the changes). And as Micky says, you can easily get the Lambda sensor checked out - or even do it yourself if it's off the bike - I'm pretty sure it's easy to check with a voltmeter.
Pluck
Sergeant Pluck
Registered user
Forgot to mention - one other thing you can do to exert some control over the mixture is keep your Throttle Position Sensor set near to top of it's range - I aim for 3.90 ish. All of this stuff has been discussed here in the past in infinite detail, so I'd also recommend an evening with the search button, but be prepared for a long evening 
Pluck
Pluck
Thanks for all the replies and info 
pomm001
Registered user
You can check the sensor with a mulitimeter but need a scope to check it properly.
Lamda performance tends to drop off with age and duty cycle, the older they get they react slower to changes in mixture up to a point where it will be noticeable in performance, silisone will poisen Lamda s.
Do a search on the subject,someone posted a while ago finding a new sensor for about £25.00,they are not bespoke to an engine just a type , someone will be along just now to give more info.
Lamda performance tends to drop off with age and duty cycle, the older they get they react slower to changes in mixture up to a point where it will be noticeable in performance, silisone will poisen Lamda s.
Do a search on the subject,someone posted a while ago finding a new sensor for about £25.00,they are not bespoke to an engine just a type , someone will be along just now to give more info.
Pykie
Registered user
How to kill a Lambda sensor
Be wary of setting about the lambda sensor with a multi-meter. I did this while trying to trace a problem on my 1100gs , and checked it out for resistance with the Ohmmeter.
The bike then mysteriously started pinking as well. I then found in a forum somewhere advice stating that Lambda sensors operate at very low volts, and the voltage a normal multimeter puts out (9 volts from a piddly little battery) is enough to zap it.
The two grey wires (this bit is from memory so don't take my word for it without checking please) feed the heater part of the sensor, which is a normal little heater element and operates at 12 volts, and can be usefully checked for resistance. The other two are from the sensor itself, and shouldn't have an ordinary ohmmeter put accross them.
I cured my fault by removing the CCP and fitting a CO2 potentiometer (which makes the ECU revert to a non-catalytic converter map), but I dont think this is possible on an 1150. I am fairly certain that I buggered my Lambda sensor with a multimeter, and that it caused my bike to 'pink' badly.
Be wary of setting about the lambda sensor with a multi-meter. I did this while trying to trace a problem on my 1100gs , and checked it out for resistance with the Ohmmeter.
The bike then mysteriously started pinking as well. I then found in a forum somewhere advice stating that Lambda sensors operate at very low volts, and the voltage a normal multimeter puts out (9 volts from a piddly little battery) is enough to zap it.
The two grey wires (this bit is from memory so don't take my word for it without checking please) feed the heater part of the sensor, which is a normal little heater element and operates at 12 volts, and can be usefully checked for resistance. The other two are from the sensor itself, and shouldn't have an ordinary ohmmeter put accross them.
I cured my fault by removing the CCP and fitting a CO2 potentiometer (which makes the ECU revert to a non-catalytic converter map), but I dont think this is possible on an 1150. I am fairly certain that I buggered my Lambda sensor with a multimeter, and that it caused my bike to 'pink' badly.
dancata
Registered user
Hi Pykie,
Does the wire from the lambda sensor have the same connection like the one from the CO2 potentiometer on a 1100GS?
I would like to change my '95 from CO2 to a lambda probe, as I can smell unburnt gas over the exhaust, and it impregnates into my riding clothing. Valves are ok, TB's are synced so it's just for fuel mixrure to fiddle with now.
Pykie
Registered user
co potentiometer to lambda sensor
The CO potentiometer lives up under the pillion seat and is a three pin connection going to a little black rubber box with a big brass slotted screw head on it. The Lamda sensor on mine is plugged into a large screw plug up above the R/H cylinder near the ecu.
I dont know nearly as much about GS's as many on this site, but it sounds like you are barking up the wrong tree. If yr bike is running that rich then there is something else wrong with it and going and fitting a lamda sensor will only confuse things more, unless the CO potentiometer or the adjustment of it is at fault. It may be quite expensive too.
I suggest that you get the CO reading at tickover checked out and adjusted. If the CO potentiometer doesnt seem to have any effect then it may be knackered, apparently they can fail.
The bike may well be running in a default 'limp home' mode which will richen the mixture up to protect the motor from damage. If it is doing this then a sensor (or the CO pot) has probably failed. Having the fault codes read (or buying an aftermarket reader) would be the best way to tell whats up.
I found that disconnecting the lamda sensor and fitting a CO pot made my bike use more fuel, but it definately ran smoother at low revs, with all traces of surging gone, and it stopped doing an odd thing where it seemed to take a 'gulp' of air on the overrun and try and cut out. I'm happier without a lambda sensor.
Hope this helps, Olly.
The CO potentiometer lives up under the pillion seat and is a three pin connection going to a little black rubber box with a big brass slotted screw head on it. The Lamda sensor on mine is plugged into a large screw plug up above the R/H cylinder near the ecu.
I dont know nearly as much about GS's as many on this site, but it sounds like you are barking up the wrong tree. If yr bike is running that rich then there is something else wrong with it and going and fitting a lamda sensor will only confuse things more, unless the CO potentiometer or the adjustment of it is at fault. It may be quite expensive too.
I suggest that you get the CO reading at tickover checked out and adjusted. If the CO potentiometer doesnt seem to have any effect then it may be knackered, apparently they can fail.
The bike may well be running in a default 'limp home' mode which will richen the mixture up to protect the motor from damage. If it is doing this then a sensor (or the CO pot) has probably failed. Having the fault codes read (or buying an aftermarket reader) would be the best way to tell whats up.
I found that disconnecting the lamda sensor and fitting a CO pot made my bike use more fuel, but it definately ran smoother at low revs, with all traces of surging gone, and it stopped doing an odd thing where it seemed to take a 'gulp' of air on the overrun and try and cut out. I'm happier without a lambda sensor.
Hope this helps, Olly.
Hong Kong Nick
Registered user
How are the secondary spark plugs? (presume you have a twin spark?)
I only ask because I had grief with my bike recently and the fuel pump was replaced .. .the guy who did it also replaced the spark plugs but somehow got the wrong ones in there ... under 3000 rpm was a pig, the bike ran rich and around 1500 rpm the thing was pinking like mad! A trip to BMW and the bike was serviced and the MAN told me that the wrong plugs were in (I didn't ask for details - riding the bike after service was just like riding a new bike) ...
Just a thought. I may not know the technicalities but this was what I was told was the problem.
Good luck.
Nick
I only ask because I had grief with my bike recently and the fuel pump was replaced .. .the guy who did it also replaced the spark plugs but somehow got the wrong ones in there ... under 3000 rpm was a pig, the bike ran rich and around 1500 rpm the thing was pinking like mad! A trip to BMW and the bike was serviced and the MAN told me that the wrong plugs were in (I didn't ask for details - riding the bike after service was just like riding a new bike) ...
Just a thought. I may not know the technicalities but this was what I was told was the problem.
Good luck.
Nick
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